Four stroke, piston driven, internal combustion engines are well known, as is the manipulation of the timing of the opening and closing of the intake and exhaust valves of such engines in relation to the position of the piston within the cylinder during each of the four strokes in conventional four stroke piston engines. In general for such engines, the intake valve is open and the exhaust valve is closed during all or most of the intake stroke, both the intake valve and the exhaust valve are closed during all or most of the compression stroke, the intake valve and the exhaust valve remain closed during all or most of the power stroke, and the intake valve is closed and the exhaust valve open during all or most of the exhaust stroke. While such engines have proven very suitable for their intended function, there is always room for improvement.